Re: Defaulting wal_sync_method to fdatasync on Linux for 9.1? - Mailing list pgsql-performance

On Wednesday 17 November 2010 01:51:28 Tom Lane wrote:
> Andres Freund <andres@anarazel.de> writes:
> > On Wednesday 17 November 2010 00:31:34 Tom Lane wrote:
> >> Well, we're not going to increase the default to gigabytes
> >
> > Especially not as I don't think it will have any effect after
> > wal_segment_size as that will force a write-out anyway. Or am I
> > misremembering the implementation?
>
> Well, there's a forced fsync after writing the last page of an xlog
> file, but I don't believe that proves that more than 16MB of xlog
> buffers is useless.  Other processes could still be busy filling the
> buffers.
Maybe I am missing something, but I think the relevant AdvanceXLInsertBuffer()
is currently called with WALInsertLock held?

Andres